The newest version of git refuses to work on repositories not owned by
the current user. This leads to issues with the /api/scmdiff endpoint:
May 27 11:16:05 myhydra hydra-server[923698]: fatal: unsafe repository ('/var/lib/hydra/scm/git/57ea036ec7ecd85c8dd085e02ecc6f12dd5c079a6203d16aea49f586cadfb2be' is owned by someone else)
May 27 11:16:05 myhydra hydra-server[923698]: To add an exception for this directory, call:
May 27 11:16:05 myhydra hydra-server[923698]: git config --global --add safe.directory /var/lib/hydra/scm/git/57ea036ec7ecd85c8dd085e02ecc6f12dd5c079a6203d16aea49f586cadfb2be
May 27 11:16:05 myhydra hydra-server[923701]: warning: Not a git repository. Use --no-index to compare two paths outside a working tree
May 27 11:16:05 myhydra hydra-server[923701]: usage: git diff --no-index [<options>] <path> <path>
I used the same solution that was used in NixOS/nix#6440.
Fixes#1214
Josef Kemetmüller
b6ea85a601